Looking into her little girl's eyes, Julie Firth suddenly caught sight of a strange reflection in one pupil.

It was the first sign of a life-threatening condition that could have cost the life of her two-year-old daughter.

To mark World Retinoblastoma Awareness Week (May 10-17), and to alert other parents to the symptoms, Julie wants to tell her story.

Today, when her daughter Isla Firth rushes around the garden wearing her favourite pink dress, there's nothing to distinguish her from other children.

Only the intense look of pride mixed with protectiveness on her mother's face says Isla might be different.

Just 18 months ago, Julie feared losing Isla, after discovering her daughter was suffering from a rare cancer.

"It seemed just a like a trick of the light when I first saw something odd about the reflection in one of Isla's eyes," she says.

"She's such a whirlwind, always rushing about full of energy, and she just happened to be lying still when I saw a weird cat's-eye reflection. I probably would have dismissed it, but when my husband Richard saw it too we thought we'd check it out to be safe."

But that chance discovery led to a diagnosis, a week after her daughter's second birthday and when Julie was eight months pregnant, which devastated the family.

Isla had retinoblastoma, a rare but fast growing eye cancer that can occur in early childhood.

In the UK, between 40 and 50 children are newly diagnosed each year, although around 98% of children survive after treatment.

In about two-thirds of children, only one eye is affected, but in one-third, tumours develop in both eyes.

"When our doctor told us it was a growth and it was cancer I felt like my heart had been ripped out," says Julie, 35, who lives in West Yorkshire.

"My mind raced with terrible thoughts of losing our beautiful girl, and Rich and I were completely devastated."

At Birmingham Children's Hospital, specialists found that the tumour was large, had already detached Isla's retina and that she had been blind in her right eye for some time.

"We were stunned, as Isla was just a normal little girl and there was nothing to suggest she couldn't see out of that eye," Julie recalls. "We felt we had failed as parents not to notice anything, but we later realised unless you are aware of the signs, it can be easy to miss."

During a two-hour operation, Isla's eye was removed and she was given an implant, with a plastic lens designed to look like her old eye.

The risk with retinoblastoma is the tumour can reach the part of the eye which contains blood vessels. If it does it may spread to other parts of the body, and in this case children are generally given chemotherapy as a precaution.

"We were so relieved to hear that Isla didn't need chemotherapy, and that her other eye was not affected," Julie says. "We felt we'd been given our little girl back."

Julie and Rich have been awed by their daughter's bravery. Never arguing or complaining about her treatment, she has braved the pain of the operation, undergone regular check-ups and adapted to living with a false eye.

"We call her artificial eye her 'magic eye' and she is gaining confidence about it - not feeling so shy about being 'different'."

As Isla did not have the genetic, inheritable form of the condition her little brother, Charlie, 16 months, is not at risk, although his eyes have been checked.

Julie and Rich's aim is to support the UK charity, The Childhood Eye Cancer Trust (CHECT) in raising awareness about retinoblastoma this week.

"Early diagnosis is so crucial, as if it is detected early the sight may be saved, and of course the cancer may not have had time to spread," she says.

"We feel so lucky that we still have our child to love and nurture, and we will do anything we can to help other parents be aware of this condition."

What is Retinoblastoma?

According to the Childhood Eye Cancer Trust, (CHECT), Retinoblastoma (Rb) is a rare but fast-growing eye cancer of early childhood.

In very young children, who have only one eye affected at diagnosis, it is possible for a tumour to develop in the second eye several weeks or even months after the diagnosis of retinoblastoma in the first eye.

Retinoblastoma occurs in two forms: a genetic, inheritable variant accounting for 45% of cases and a non-genetic, non-inheritable form.

The number of tumours found in the eye also varies: sometimes only one tumour develops at the back of the eye, but frequently there are several tumours, and these may require more than one type of treatment.

How do I spot it?

Sometimes the light or flash from a camera can cause the pupils (the black circle in the middle of the eye) to look white in a photograph.

This could be due to the angle of the light when the photograph was taken or it can be a sign of something more serious, but it need not be retinoblastoma.

Other signs could be if the pupil flashes white - a bit like a cat's eyes caught in the beam of a car headlights.

You may notice this white reflection (called a reflex) in some artificial light, not just in a photograph. Or that the inside of the eye looks like jelly or is cloudy, one pupil is red and the other is black and looks 'wrong'.

The eye may also be red and swollen and sometimes the child may have a squint.

What should I do?

If you are concerned about your child and recognise any of the symptoms above you should ask your GP or Optician to do a test for the red reflex.

There are a number of different treatments available and the aims of treatment are firstly, to preserve the life of the child, secondly, to preserve vision and thirdly, to minimise any complications or side-effects of treatment.